Narcolepsy: welcome to neuroimmunology!

A recent report in Science Traslational Medicine (1) has deserved a lot of attention by mainstream media. Headlines referred to it as the confirmation that narcolepsy is an autoimmune disease. Narcolepsy is an interesting disease both clinically (sleep attacks, cataplexy, sleep paralysis, visual hallucinations during early sleep and awakening…) and pathophysiologically. Current knowledge points at a selective death or damage in the neurons of the anterior part of the hypothalamus responsible of orexin production. Orexin (or hypocretin) is a secreted proteic neurotransmitter that regulates awakeness and apettite and whose levels in CSF are significantly lower in patients with narcolepsy than in controls. As usual, the exact cause of narcolepsy is unknown, although recent studies suggest that an autoimmune response, probably triggered by an environmental factor (let’s say, a virus), is the key process in its development (2).The paper by De la Herrán-Arita and colleagues reports an interesting, well-performed study that, contrary to what mainstream media say, does not demonstrate that narcolepsy is an autoimmune disease. But we’ll come to that later. The autoimmune hypothesis of narcolepsy is not new at all. Among the genes that have been associated to narcolepsy, most play important roles in the immune system (3). The strongest association was found with the HLA-DQB1*0602 allele, which more than 95% of the narcolepsy patients carry. But other genes, related to the immune system have also been implicated (4). However, as in any other complex disease, genes don’t explain everything. What the HLA system does is to present antigens (the targets of an immune response, regardless of it is against a pathogen or an autoimmune one) to T cells (lymphocytes) and T cells are the ones enabled to kill a cell carrying that antigen or to call other cells so they are the ones killing the antigenic cell.  One

Continue reading

KIR4.1 antibodies: A revolution in multiple sclerosis

This week we had the opportunity to read a paper in the New England Journal of Medicine, describing, in my opinion, a breakthrough finding in MS. It’s published by Srivastava and coworkers, from the University of Munich. It describes the presence of antibodies against the KIR4.1 potassium channel in almost 50% of MS patients. Maybe i’m biased because my research is focused in autoantibodies in neuroimmune disorders, but, in my opinion is one of the best papers that has been published in MS in many years for different reasons that i will describe later. However, the impact in the mainstream scientific media and in the community has not been very big so far. It has had a media coverage that is, for example, far behind a recent study describing some allele variants having a small genetic risk of developing MS, being, in my opinion, much less important from the patient care point of view. The study is an example of how research should be conducted. From a very good (and old) hypothesis it develops a set of experiments brilliantly designed to achieve, with success, the goal in a completely unbiased approach. The approach is very similar to what Dr Dalmau and co-workers have been doing with autoimmune encephalitis, but it has some key differences that make the study even better if possible. Briefly, the study starts describing a set of patients that react agains glial components of the central nervous system. Then the authors isolate cell membranes from brain tissue (rat and human). They demonstrate reactivity against those membranes and isolate the proteins to which the antibodies are targetted (being that protein KIR4.1). Then they design another set of experiments to confirm the finding. They use ELISA, flow cytometry and immunocytochemistry to define the specificity of the antibodies and their

Continue reading

Pills for multiple sclerosis

It’s been a while since i wrote last post, but NeuroImmunology has been busy with several other projects. It’s been a while too since i decided to write a monographic post about the different oral treatments that are already available or are about to arrive but i postponed it until i had enough time to do it carefully. I will try to clarify the different pros and cons of the oral treatments in general and of each one in particular. It’s also an attempt to organize my ideas about the subject. Until very recently the only disease-modifying treatments available for MS were injected therapies (I say disease-modifying because steroids are only used for relapses and do not modify the course of the disease in the long-term). Interferon and glatiramer acetate (subcutaneous or intramuscular), mitoxantrone (intravenous) and, more recently, natalizumab (intravenous) were the only available options for MS. In some countries people used intravenous immunoglobulins (IVIg), azathioprine (oral) and cyclophosphamide (oral or intravenous) but the evidence for their use in MS is very weak and they were not considered standard treatments for MS. Several major claims and complaints of patients with MS related to the treatment route of administration. Needles, need for portable fridges, problems in the airports and customs, an injection every two days, subcutaneous nodules, risk of infections… So, research on oral therapies was one of the main targets of researchers and companies and one of the things patients are more interested and askabout more often. And oral therapies finally arrived. At this moment there is only one treatment fully available in Europe, fingolimod (Gilenya), four more laquinimod, BG-12 (dimethyl fumarate) teriflunomide and cladribine have completed phase III trials and another one, firategrast, is still on phase II trials but shows promising results. The first and most obvious advantage

Continue reading

Does multiple sclerosis start from the gut?

MS scientific literature is fascinating. Few neurological (and non-neurological) diseases can compete in number of papers, impact factor and mainstream media attention. However many research projects use classical animal models (experimental allergic encephalmyelitis, EAE) and those animal models have been an enormous source of erroneous extrapolations to MS pathogenesis. Many times the EAE model has been a research target itself and not because the results it could provide truly matched with what we want to know about MS. However, despite the noise that animal models generate, it must be aknowledged that they have evolved into more accurate models and have boosted MS research and knowledge. I like the “from bedside to bench” approach and not the other way round but, sometimes, basic research works initiate breakthrough hypothesis that deserve “bedside” research. I bring up this statement after reading the paper Commensal microbiota and myelin autoantigen cooperate to trigger autoimmune demyelination by Kerstin Berer and co-workers and published in Nature in October 2011. The hypothesis is beautiful (but not new) and, although it probably needed a lot of experiments and comprobations, methods are pretty simple. They used a mouse model of spontaneous relapsing remitting MS, in which CD4 T cells constitutively express a T cell receptor that recognizes myelin oligodendrocyte glycoprotein peptides. They start with the observation that this model develops MS in variable proportions depending on the research group using the model. Then they wondered if the way these mice were bred had any influence in encephalomyelitis development and bred them in two different conditions: a conventional pathogen free (or SPF) environment or in a complete germ-free environment. In SPF breeding commensal microbiota can grow and animals are only pathogen-free. In germ-free environment animals don’t have commensal microbiota. The main goal was to see if there were differences in MS

Continue reading

Fingolimod unexpected death

A few days ago we had access to this alert in Medscape. An MS patient, that had completed the 6-hour vigilance period after the first dose of fingolimod, died unexpectedly the next day.  We don’t know much about it and we should wait until this case is resolved and an official report released. We only know that the patient was already taking beta-blockers and calcium channel antagonists, with bradycardia among their side effects. However, it re-inforces my view that Fingolimod safety has to be carefully followed-up. Anyway, one important message is that an oral treatment, a pill, does not necessarily have to be safer than a biological treatment. It may be easier to take for patients but not necessarily innocuous.

Continue reading

Rituximab vs Ocrelizumab in multiple sclerosis

Two weeks ago the annual meeting of the ECTRIMS was held in Amsterdam. As usual, several interesting presentations, some of them probably good enough to change the immediate future of MS clinical practice, were presented. Among them, new data regarding the next 3 new oral therapies that probably will be approved when their results are published, laquinimod, teriflunomide and BG-12. These therapies will need a specific review later on. But the focus of this post is on the data of the phase II trial testing Ocrelizumab in MS. Ocrelizumab is a humanized monoclonal antibody targetting the CD20 B-cell marker. It depletes B lymphocytes. It is the molecular and commercial son of Rituximab and the diseases to which is aimed are the same as Rituximab. In fact, what we all expected was that Ocrelizumab improved safety and reduced infussion reactions due to its humanized nature (while Rituximab is chimeric). Rituximab had been tested before in MS with notable success. However, as we explained before, that study did not lead to a phase III trial due to commercial interests. Then its humanized version was tested expecting more safety and tolerability. But it happened that, paradoxically, Ocrelizumab turned out to be less safe. At least, while in Rheumatoid Arthirtis and Lupus Rituximab severe adverse events were very infrequent, their trials with Ocrelizumab were prematurely halted because of several fatal opportunistic infections. In MS the Ocrelizumab phase II trial was continued and, again, a death in the Ocrelizumab arm raised concerns regarding its safety. Now we have additional data regarding both safety and effectiveness. The 96 week results of the phase II trial of Ocrelizumab in MS were presented in ECTRIMS and simultaneously published in Lancet. Effectiveness data are extraordinary. Reduction of 89-96% of the rate of new gadolinium-enhancing lessions and around 80% for

Continue reading

Interferons, get out!

Today New England Journal of Medicine makes public the results of a large clinical trial with more than a thousand patients comparing results of teriflunomide against placebo in MS. Results are not spectacular, but not bad. It decreased a 30% the annualized relapse rate and reduced the rate of disability progression slightly. The best point in favour of teriflunomide is the adverse reactions profile, comparable to that of placebo. That, together with it being oral, makes it a perfect candidate for first-line therapy and likely to be suitable for a combination trial with interferons/glatiramer acetate. Another good point in favour of teriflunomide is that it shows effectiveness in a 2-year trial, which makes results stronger. It’s the third oral treatment showing good results in a phase III trial in MS and, probably, the second one to be approved. Fingolimod is already being used in the USA, and has been approved in Europe, but it scares a little bit and that will play against it when teriflunomide comes out. The third one, cladribine, is at serious risk of being left aside. Moreover, a fourth one, Laquinimod, will be another safe option for first-line therapy in a while although phase III data are still pending. In a few months we’ll have, at least, two oral therapies for MS that will broaden the therapeutic options and will allow to switch patients to safe, tolerable options that, to date, were restricted to painful injected treatments or powerful (but scaring) drugs. Hope teriflunomide approval and commercialization does not take the long, shameful process that Fingolimod is suffering. In February 2010 results were published… and here we still have to give excuses to patients…

Continue reading

What’s going on disimmune peripheral neuropathies

Last June NeuroImmunology attended the 2011 Biennial meeting of the Peripheral Nerve Society in the Bolger Center, Potomac (MD). We were obviously interested in disimmune disorders but, we must recognize that, probably, breakthrough, surprising and interesting works were outside our field. Genetic and acquired neuropathies sessions showed, in our oppinion, a higher level than disimmune neuropathies ones. However, the whole meeting was pretty interesting and some useful conclusions made us think that past work may be starting to give results. I have several comments and remarks regarding disimmune neuropathies: For me, the first and most important conclussion is the desperate need we have in knowing a lot more of disimmune neuropathies pathogenesis: Guillain-Barré syndrome studies are focused almost exclusively in antiganglioside antibodies (which, to date, are the best and more solid research line in these disorders) and don’t seem to point in any other direction, cause or mechanism. However, the ambitious GBS multicentric database projected by Dr Jacobs’ group will, for sure, help in performing other kind of studies, genetic, pathologic and immunopathogenic. We hope we can move on antiganglioside antibodies and see beyond. Dr Huizinga, from Dr Jacobs group, presented their job on dendrictic cell role in GBS pathogenesis and molecules implicated in dendritic cell priming of B cells. It seems that new, non-antiganglioside, works are arising. Regarding antiganglioside antibodies, all posters presented by Dr Willison and Yuki groups were also remarkable. CIDP is, by far, the less known of all disimmune neuropathies. We still debate if auto-antibodies or T cells are the effectors. Immunopathogenic studies are scarce, weak and based in imperfect models (modified from multiple sclerosis ones, like experimental autoimmune neuritis – EAN- ). The most remarkable work in CIDP and related diseases was presentation by Gerd Meyer zu Horste, from Dr Kieseier’s lab, showing a new

Continue reading

Extraordinary claims…

… require extraordinary evidence. That is the heading of a “Message from the Editor” in Annals of Neurology published online in April 2011. It comments on a paper demonstrating the absence of retroviral particles in CSF of patients with chronic fatigue syndrome while criticizes the role of publishers (and researchers)  paying (too much) attention to breakthrough discoveries while they don’t care much about those same discoveries when they fail to be replicated. It also points out the role of mainstream media and the internet in amplifying these “extraordinary claims” and highlight the need of humble statements and careful replication before attracting mainstream media focus on those claims. They, as we did, compare the case with that of the CCSVI (the other way, though) and remember us the necessary slowness of science: ” […] as journal editors we have a responsibility to do everything possible to insure that data appearing in our pages will stand the test of time.” The only thing i don’t like in that necessary message is that it will remain within the limits of Annals of Neurology readers. That is the battle clinicians and researchers need to win. The one outside the official means. If we fail to convey this message out of our limits we will lose the battle against bad, harmful, attractive science. So the scientific community has to grow public but grow around our own environments, both our clinics and, more importantly, our communities.

Continue reading